You are right, I haven't memorized all the good powerup locations yet. I mostly pick up the double/triple ones like the double repulsificator at the fairground and beaver mountains, and of course the amazing acme damage modifier in group 4 race 2, and the granite car to kill big plow.
Not sure what you mean by not using the recover button, I feel like I use it quite a lot.
I'm going to submit this one to speedrun.com. didn't submit the previous one due to the "cheat" at uss lweinsky. My latest run is Clean.